Early-Onset Colorectal Cancer: What Do We Know?

Andrea Cercek, MD: There’s a rising interest in early-onset colorectal cancer, and this has to do with the fact that in the United States, as well as worldwide in developing countries, we have noted an increase in incidence in patients under 50. This is a patient population for whom we don’t have screening guidelines. In fact, we don’t recommend screening until 50 or older, and yet they are developing colorectal cancer. One of the questions that of course arises is, what are the predisposing factors? What’s interesting about this population is that they are not all familial.

We know that patients with Lynch syndrome, patients with ulcerative colitis, have an increased incidence of colorectal cancer in this young age group. But these patients don’t have any of those predispositions. They don’t even necessarily have any family history, certainly not a family history of cancer in relatives younger than 50.

So, something is going on. There is very likely an environmental factor that is contributing to this rise. What’s interesting as well is that some of the data presented at this meeting, and also from the prior publications of the SEER (Surveillance, Epidemiology, and End Results Program) database, show that these tumors appear to be predominantly left-sided, predominantly rectal. We really don’t know why that is, if there is perhaps a different driver or if this is obesity or if this is microbiome driven. Those are some of the research questions that are still ongoing and some of the things that were discussed at the meeting today.

The major take-home point, at this time, for community oncologists, but even more so for internists and gastroenterologists and primary care providers, is not to dismiss symptoms of rectal bleeding, bloating, and abdominal pain. That is how the majority of these patients present. That was clearly presented at today’s meeting, as well as at ASCO GI. See if these are symptoms, follow them up to recommend a colonoscopy. At this time, I think it’s too soon to say that we should do screenings at 45 and older or 40 and older, simply because, although the incidence is on the rise, it’s still low relative to the population that would need to be screened.

For community oncologists, the data suggest that these patients present with more aggressive tumors. There have been some data that show they don’t do as well, they present at a later stage. It’s really unclear whether they present with later-stage disease because their disease is more aggressive or because they actually dismiss their symptoms until they develop advanced disease and then are diagnosed at a later stage. We don’t know very much about how they respond to chemotherapy.

Some of the data at today’s meeting indicated that patients actually do better per stage as compared to the average-onset patients, possibly due to a better ability to tolerate chemotherapy or possibly because their disease is more responsive. I think it’s really a question of the biology. At least with what we’ve seen so far, including the analysis of the Oncotype DX in early-stage patients, there really didn’t seem to be a very significant difference between the younger patients and the average-onset patients who are in their late 60s or 70s.

I wouldn’t recommend a change in treatments at this point for community oncologists. I think younger patients, from the data presented at today’s meeting, too, are treated a bit more aggressively and are more likely to get chemotherapy. That is probably a combination of the oncologists trying to do what they can to treat the disease and then the patients being very motivated and wanting the most aggressive treatments.

Transcript Edited for Clarity

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Transcript:

Andrea Cercek, MD: There’s a rising interest in early-onset colorectal cancer, and this has to do with the fact that in the United States, as well as worldwide in developing countries, we have noted an increase in incidence in patients under 50. This is a patient population for whom we don’t have screening guidelines. In fact, we don’t recommend screening until 50 or older, and yet they are developing colorectal cancer. One of the questions that of course arises is, what are the predisposing factors? What’s interesting about this population is that they are not all familial.

We know that patients with Lynch syndrome, patients with ulcerative colitis, have an increased incidence of colorectal cancer in this young age group. But these patients don’t have any of those predispositions. They don’t even necessarily have any family history, certainly not a family history of cancer in relatives younger than 50.

So, something is going on. There is very likely an environmental factor that is contributing to this rise. What’s interesting as well is that some of the data presented at this meeting, and also from the prior publications of the SEER (Surveillance, Epidemiology, and End Results Program) database, show that these tumors appear to be predominantly left-sided, predominantly rectal. We really don’t know why that is, if there is perhaps a different driver or if this is obesity or if this is microbiome driven. Those are some of the research questions that are still ongoing and some of the things that were discussed at the meeting today.

The major take-home point, at this time, for community oncologists, but even more so for internists and gastroenterologists and primary care providers, is not to dismiss symptoms of rectal bleeding, bloating, and abdominal pain. That is how the majority of these patients present. That was clearly presented at today’s meeting, as well as at ASCO GI. See if these are symptoms, follow them up to recommend a colonoscopy. At this time, I think it’s too soon to say that we should do screenings at 45 and older or 40 and older, simply because, although the incidence is on the rise, it’s still low relative to the population that would need to be screened.

For community oncologists, the data suggest that these patients present with more aggressive tumors. There have been some data that show they don’t do as well, they present at a later stage. It’s really unclear whether they present with later-stage disease because their disease is more aggressive or because they actually dismiss their symptoms until they develop advanced disease and then are diagnosed at a later stage. We don’t know very much about how they respond to chemotherapy.

Some of the data at today’s meeting indicated that patients actually do better per stage as compared to the average-onset patients, possibly due to a better ability to tolerate chemotherapy or possibly because their disease is more responsive. I think it’s really a question of the biology. At least with what we’ve seen so far, including the analysis of the Oncotype DX in early-stage patients, there really didn’t seem to be a very significant difference between the younger patients and the average-onset patients who are in their late 60s or 70s.

I wouldn’t recommend a change in treatments at this point for community oncologists. I think younger patients, from the data presented at today’s meeting, too, are treated a bit more aggressively and are more likely to get chemotherapy. That is probably a combination of the oncologists trying to do what they can to treat the disease and then the patients being very motivated and wanting the most aggressive treatments.